France
20 mm/90 (0.79") GIAT M693 (15B) CN-MIT-20F2
20 mm/73 (0.79") GIAT M621 (15A)
Updated 03 March 2012
The 20F2 is the navalized version of the GIAT CN-MIT 20 M693 (Canon Mitrailleur 20 mm Modèle 693), formerly the Hispano-Suiza 820.  This weapon is also used by the French Army.

The M621 is a low-recoil gun which has been mainly used on helicopters and small aircraft, but a navalized version was developed in the late 1980s.  Recoil is minimized by the use of a muzzle brake and a shock-absorbing mount.
WNFR_2cm-90_Giat_La_Fayette_pic.jpg

20 mm/90 M693 on Frégate La Fayette (F 710)
Marine Nationale Photograph
WNFR_2cm-90_Giat_M693_pic.jpg

20 mm/90 M693 on Affût 15B Naval Mounting
Photograph copyrighted by GIAT and courtesy of Naval Technology
WNFR_2cm-90_Giat_M621_pic.jpg

20 mm/73 GIAT M621 on Affût 15A Naval Mounting
Note the safety rail
Photograph copyrighted by GIAT and courtesy of Naval Technology
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Gun Characteristics
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Designation 20 mm/90 GIAT M693 CN-MIT-20F2
20 mm/73 GIAT M621
Ship Class Used On France:  Florèal, Tripartite minelayers, P400, CDIC and EDIC classes
Belgium:  Tripartite minelayers
Indonesia:  Tripartite minelayers
Malawi:  Kasunga
Netherlands:  Tripartite minelayers
Pakistan:  Tripartite minelayers
Saudi Arabia:  NAJA 12 class
Date Of Design Late 1970s
Date In Service 20F2:  1983 (Naval Version)
M621:  1988 (Naval Version)
Gun Weight 20F2:  N/A
M621:  104 lbs. (47 kg)
Gun Length oa 20F2:  N/A
M621:  87 in (2.207 m)
Bore Length 20F2:  about 71 in (1.800 m)
M621:  about 57 in (1.460 m)
Rifling Length N/A
Grooves N/A
Lands N/A
Twist N/A
Chamber Volume N/A
Rate Of Fire 20F2:  800 rounds per minute cyclic
M621:  740 rounds per minute cyclic
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Ammunition
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Type Fixed
Weight of Complete Round 20F2 - HE - 0.562 lbs. (0.255 kg)
M621 - N/A
Projectile Types and Weights 20F2
   HE - 0.265 lbs. (0.120 kg)
   APDS - 0.238 lbs. (0.108 kg)

M621
   HE - 0.223 lbs. (0.101 kg)
Bursting Charge N/A
Projectile Length N/A
Propellant Charge N/A
Muzzle Velocity 20F2
   HE - 3,440 fps (1,050 mps)
   APDS - 4,100 fps (1,250 mps)

M621
   HE - 3,215 fps (980 mps)
   AP - 3,380 fps (1,030 mps)
Working Pressure N/A
Approximate Barrel Life 16,000 rounds
Ammunition stowage per gun
(on mount)		 20F2:  320 rounds in two 160-round magazines
M621:  160 rounds in single magazine
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Range - 20F2
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Elevation With 0.562 lbs. (0.255 kg) HE
Effective HE - 2,200 yards (2,000 m)
AP - 1,300 yards (1,200 m)
Maximum HE - 10,960 yards (10,020 m)
AP - 7,400 yards (6,770 m)
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Mount / Turret Data
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Designation 20F2:  Affût 15B
M621:  Affût 15A
Weight 15B:  688 lbs. (312 kg) without ammunition
15A:  417 lbs. (189 kg) without ammunition
Elevation 15B:  -10 / +40 degrees
15A:  -10 / +40 degrees
Elevation Rate Manual Elevation, only
Train -170 / +170 degrees
Train Rate Manual Training, only
Gun recoil N/A
Note:  These mountings use a collimator gunsight.
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Data from
"The Naval Institute Guide to World Naval Weapon Systems 1991/92" and "1994 Update" both by Norman Friedman
"Rapid Fire" by Anthony G. Williams
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Page History

21 May 2006 - Benchmark
03 March 2012 - Updated to latest template